Bag or bundle-type packaging with no plastic elements and high protection from moisture and water

ABSTRACT

The present utility model refers to a bag or a bundle-type packaging suitable to contain cement or other similar material, consisting of at least one sheet of paper wherein the external sides of said sheets are coated with at least one layer of hydrophobic paint. 
     This paint transfers water-repellent characteristics to the paper; in this way, both the transmission of moisture/water vapor (WVTR) and the absorption of water (COBB) are significantly reduced. 
     In fact, thanks to at least one layer of paint applied externally to the sheets of paper that make up the bag, the water is not retained by the paper, but slips away due to the high surface tension present on the treated paper. 
     The barrier effect is thus increased compared to that obtainable from standard bags known in the art, thus guaranteeing the product contained inside the bag a high protection from humidity, even in the absence of intermediate polythene sheets in the manufacture of the bag and, consequently, improving the shelf life of the product contained inside the bag. 
     The bag achieves these results even though it has no intermediate plastic layers.

TECHNICAL FIELD

This utility model refers to a bag or bundle-type packaging for the transport of materials. In particular, this utility model refers to a bag or bundle-type packaging to contain or wrap paper, cement or other material useful in various food, chemical, building sectors, free of plastic elements (“plastic free”) and with high resistance to humidity and water.

STATE OF ART

Currently, bags made of paper and plastic are used for the transport of cement and other similar materials in the construction sector, as well as for the transport of other goods, for example in the food and chemical sectors, and for the transport of minerals.

Typically, the bags known in the art consist of two overlapped sheets of paper of the type, for example, of 80 gr/m², between which a plastic sheet is interposed, typically high-density polyethylene (HDPE), or with a density in the range between 0.945 and 0.965 g/cm³ and a thickness of, for example, about 7 microns.

These bags show a fair resistance to humidity, even if stored for a long time in a humid environment.

However, these bags have the drawback of containing plastic elements; considering the very high number of bags of this type used all over the world for the transport of various materials, the fact of containing plastic elements constitutes a serious problem from an environmental point of view.

Therefore, the Applicant has posed the technical problem of how to efficiently and economically manufacture plastic-free bags or packaging for the transport of cement, glue and other similar material, which are in any case capable of preserving the material they contain from humidity.

TABLE OF CONTENTS

In a first aspect, the present utility model refers to a bag or bundle-type packaging such as that detailed in claim 1.

The Applicant of the present application has in fact surprisingly found that the technical problem encountered above can be solved in an effective and reliable way by means of a bag or a bundle-type packaging suitable for containing paper, cement or other similar material, consisting of at least two sheets of paper overlapped one to the other, wherein the outer sides of said sheets are coated with at least one layer of hydrophobic paint. Furthermore, said paint is distributed on each of said sheets of paper with a weight in the range from about 4 gr/m² to about 9 gr/m².

The term “bag” in the present description and in the attached claims means a bag, a small bag or any container or packaging of the bundle type that is printable with inks and paints, suitable for safely transporting and preserving the material it contains intact, this material being of solid, semi-solid or granular form, of the various product classes such as, for example, soil, sand, cement, stucco or other material useful in the construction sector, as well as animal feed, seeds, food for animals and food for people or other material useful in the food or chemical sector or for the transport of minerals and the like, and this container being such that it can assume the shape determined by the material in its entirety contained within it.

In particular, the term “bundle-type packaging” means a single sheet of paper or paper coupled with another material, both paper and plastic material.

Typical examples of packaging of the bundle type are, for example, a bundle for paper for photocopy, for rolls of absorbent paper for use in the kitchen, for biscuits, for food products in general and not, for sugar sachets, and the like.

Thanks to the fact that the hydrophobic paint is distributed on the outer side/face of the paper sheets that make up a bag or bundle-type packaging and not, therefore, on the face facing the inside of the bag or bundle-type packaging, the contact between the paint and the product contained inside the bag or bundle-type packaging is avoided.

This paint transfers water-repellent characteristics to the paper; in this way, both the transmission of moisture/water vapor (WVTR) and the absorption of water (COBB) are significantly reduced.

In fact, thanks to the at least one layer of paint applied externally to the sheets of paper that make up the bag or bundle-type packaging, the water is not retained by the paper, but slips away due to the high surface tension present on the treated paper.

In this way a highly hydrophobic surface is obtained in the broadest sense of the term, to indicate the property of not absorbing and not retaining water.

The barrier effect is thus increased compared to that obtainable from standard plastic bags known in the art, thus guaranteeing high protection from humidity to the product contained inside the bag or bundle-type packaging, even in the absence of sheets in intermediate polythene plastics in the manufacture of the bag, and consequently improving the shelf life of the product contained within the bag.

In particular, the bag or bundle-type packaging of this utility model is free of plastic elements (“plastic free”), while maintaining high shelf storage performance against humidity and water.

According to a preferred embodiment, said bag or bundle-type packaging consists of at least three, such as three, four, five or a greater number of sheets of paper overlapped on each other.

According to a preferred embodiment, said hydrophobic paint is of the water-based wax type, such as, for example, a polymeric wax.

According to a preferred embodiment, said hydrophobic paint is a mixture that contains at least one element of the isothiazol-3-one type, such as 1,2-benzisothiazol-3(2H)-one, 5-chloro-2-methyl-2H-isothiazol-3-one (CMIT) and/or 2-methyl-2H-isothiazol-3-one, and mixtures thereof.

According to a preferred embodiment, said hydrophobic paint has a pH between 8 and 9.

According to a preferred embodiment, said hydrophobic paint has a relative density of about 1 g/cm³ at 20° C.

According to a preferred embodiment, said hydrophobic paint has a viscosity <2000 mPas, preferably <1500 mPas.

According to a preferred embodiment, said paint is distributed on each of said sheets by means of the spreading process, that is an industrial process that includes the uniform application of said paint on said sheets, drying through an oven, eventual calendaring or embossing, and subsequent cooling.

According to a preferred embodiment, said bag consists of a main lateral external surface and at least one lower bottom secured to said main external surface, wherein each of said main lateral external surface and said lower bottom consists of at least two of said sheets of paper overlapped on each other coated with at least one layer of hydrophobic paint.

In this way the bag is as if it was made up of a single body.

Preferably, the consistency of the external lateral surface of the bag is such as to allow the bag itself to assume the shape defined by the mass of the material contained therein.

Preferably, said lower bottom has a flat, partially rigid surface, such as to be able to act as a ground support base for the bag. In this way, having this lower bottom a substantially flat dimension, it is easier to rest the bag on the ground on flat surfaces in a vertical position when the bag is full or partially full.

In one embodiment, preferably, said bag also consists of an upper bottom, substantially similar to the lower bottom; in this way, it is possible to place the bag on the ground either by using the lower bottom as a support base on the ground, or, vice versa, by using the upper bottom as such a support base. This is particularly useful when the bag to be placed on the ground does not have a part that must necessarily be facing upwards and one facing upwards.

According to a preferred embodiment, said upper bottom consists of at least two of said sheets of paper overlapped on each other coated with at least one layer of hydrophobic paint.

In an alternative embodiment, the bag of the present utility model is of the type defined as “open mouth”, where said upper bottom is not present; the bag in this alternative embodiment in fact has the upper part of the lateral surface open so that it can be easily filled. Once the bag has been filled, this opening is closed with special sealing machines.

According to a preferred embodiment, the internal sides of said at least two sheets are glued to each other at the upper and lower ends of said sheets in order to create a sort of tube inside the bag.

According to a preferred embodiment, the internal sides of said at least two sheets are glued to each other at points arranged at said upper and lower ends.

According to a preferred embodiment, the internal sides of said at least two sheets are glued to each other by means of starch glue or vinyl glue.

According to a preferred embodiment, said paper can be chosen from the group consisting of paper of the Kraft type, of the high porosity Kraft type, glossy paper, semi-extensible paper, Yankee paper or a type of wrapping paper provided with a glossy and shiny face and the other rough, one glossy or matte side, Duplex smooth paper, cardboard and the like.

Preferably, each of said paper sheets of said main lateral external surface of said bag has a weight per square meter of the order of from about 70 to about 120 gr/m², preferably of about 90 gr/m².

Preferably, said bottoms have a grammage per square meter of from about 60 to about 100 gr/m², preferably of about 90 gr/m².

According to a preferred embodiment, said bag further comprises closure systems along a longitudinal line of the external lateral surface of the bag that substantially extends from said lower bottom to said upper bottom, wherein said closure systems comprise escape routes to ensure the escape of air from the inside of the bag.

In this way, a better total deaeration of the bag is obtained.

According to a preferred embodiment, said bag comprises at least one polythene sheet interposed between two of said layers of paper coated with said hydrophobic paint.

In this way, the transmission of moisture/water vapor (WVTR) inside the bag is further reduced.

In a second aspect, the present utility model refers to a bag or bundle-type packaging such as that indicated in claim 10.

The Applicant of the present application has in fact surprisingly found that the technical problem encountered above can be solved in an effective and reliable way by means of a bag or bundle-type packaging suitable for containing paper, cement or other similar material, consisting of a single sheet of paper, possibly coupled with at least another sheet of paper or plastic material, wherein the outer side of said bag or bundle-type packaging is coated with at least one hydrophobic paint layer having a weight in the range from about 4 gr/m² to about 9 gr/m².

In this way, it is possible to wrap reams of paper, rolls of absorbent paper for use in the kitchen, biscuits, sugar sachets, food products in general and not with a bundle-type packaging, also consisting of a single sheet of paper covered with at least one layer of hydrophobic paint. This hydrophobic paint layer allows the products contained within the bundle-type packaging to be preserved from moisture, allowing them to be stored for a long time on the shelf.

Further features and advantages of this utility model will be better highlighted by examining the following detailed description of preferred, but not exclusive, embodiments, shown only as an indication and not limitation with the support of the attached drawings. In particular, in such drawings:

FIG. 1 is a view of an empty bag according to an embodiment of the present utility model, wherein the lower bottom and the upper bottom folded on the lateral surface are visible;

FIG. 2 schematically shows how the two sheets of paper that make up the bag are glued to each other;

FIG. 3 shows another embodiment of the bag of the present utility model, wherein the escape routes are visible along the longitudinal line;

FIG. 4 shows a side view of FIG. 3, wherein the escape routes along the longitudinal line are further visible.

DETAILED DESCRIPTION

The following detailed description refers to particular embodiments of the device of the present utility model, without limiting its content.

The bag of this utility model is suitable for containing cement or other similar material useful in the construction or in the food, mineral, chemical sector, such as sand, gravel or other material useful for example in the feed and seeds sector for animals or the like.

Example 1 (of the present invention). The bag 1 shown in FIG. 1 consists of a main lateral external surface 2, a lower bottom 3 and an upper bottom 4 secured to the main external surface 2, so as to make the bag 1 appear as if it were made up of a sole body.

The lower bottom 3 and the upper bottom 4 comprise a flat, partially rigid surface, such that it can be folded onto the side surface 2 when the bag is empty, so as to be able to store the bag occupying the minimum necessary space, and so as to be able to act as the base of the bag, when it is at least partially full and placed in a vertical position.

Bag 1 consists of two sheets of paper; in particular, the bag consists of an outer sheet of semi-extensible paper, having a weight of about 90 gr/m², overlapped on an internal sheet of semi-extensible type of paper also having a weight of about 90 gr/m². The outer sheet has a width that extends at least 20 mm with respect to the width of the inner sheet, to facilitate longitudinal gluing.

The inner and outer sheets of paper of the lower bottom 3 and the upper bottom 4 each have a weight slightly of about 70 gr/m².

The internal and external paper sheets both of the side surface and of the bottoms are coated by spreading with a layer of hydrophobic paint of the polymer wax type, with a coverage of about 5 gr/m². The hydrophobic paint used is a mixture that contains 1,2-benzisothiazol-3(2H)-one, 5-chloro-2-methyl-2H-isothiazol-3-one (CMIT) and 2-methyl-2H-isothiazol-1-one, with a pH of about 8.5, a relative density of about 1 g/cm³ at 20° C. and a viscosity <1,500 mPas.

The internal sides of the two internal and external sheets of paper are glued to each other at their upper and lower ends by means of a transverse gluing, so as to create a sort of tube inside the bag (see FIG. 2). The gluing between the sheets takes place by points 7 arranged at their upper and lower ends, using starch glue.

The bag 1 is not provided with holes like some conventional bags known in the art.

As shown in FIGS. 3 and 4, the bag is also equipped with escape routes 6, arranged along the longitudinal line 5, consisting of aeration zones created by the absence of glue in these points, to facilitate the escape of air from the inside the bag.

The bag 1 is filled with cement or other similar material as indicated above, and subsequently suitably closed according to the traditional methods of filling and closing these types of bags. For example, the cement can be inserted inside the bag through an opening obtained in this lower bottom 3, an opening that is subsequently closed automatically at the end of the filling phase of the bag, by means of a particular valve with which this lower bottom 2 is provided. The bag thus filled and then closed is subjected to continuous exposure to water for at least 7 days.

Example 2 (Comparison)

As a comparison example 2, a bag is taken and differs from the bag of the invention shown in Example 1 in that the two sheets of paper that compose it have not been coated with a layer of hydrophobic paint.

Test

Example 1 of the present invention and Example 2 of comparison have been subjected to various tests described below to verify their properties.

Test 1: the Gurley method was used, as described in ISO 5636-5 standard to determine the air permeability of paper sheets, with air permeability between 0.1 μm/(Pa·s) and 100 μm/(Pa·s), expressing the test results in seconds.

Test 2: the Cobb method described in the European EN ISO 535 standard was used to determine the water absorption of paper, using 3 different contact times (60 seconds, 120 seconds, 300 seconds) and expressing the test results in g/m².

Test 3: the test method described in ISO 3781 standards was used to determine the tensile strength properties of the paper sheets after immersion in water (wet strength), expressing the test results as a percentage.

Test 4: the test method described in ASTM E96//E96M-15 standards, procedure E, was used to determine reliable values of water vapor transmission (WVT) through the paper sheets, both in the standard environmental condition of 23° C. and 50% relative humidity and in extreme tropical conditions of 38° C. and 90% relative humidity, expressing the test results g/m² for 24 hours.

Table 1 below shows the results of the various tests.

TABLE 1 Test 4 Test 4 Test 2 Test 2 Test 2 23° C. 38° C. Test 1 60 sec. 120 sec 300 sec Test 3 50% RH 90% RH Sample Structure sec. m² m² m² % m² m² 1 2 sheets + 7,200 4.7 5.5 5.6 10% 115 735-757 invention paint 2 2 sheets 20 30.6 37.5 43.7 = 578-740 4111-4574 comparison with no paint Result 1/2 360 1/6 1/7 1/8 +10% 82% 80%

From Table 1 it can be seen that sample 1 of the present invention, wherein the two paper layers have been coated with hydrophobic paint, in the absence of intermediate plastic layers, improves air permeability by 360 times (Gurley test 1) compared to comparison sample 2. Furthermore, the sample 1 of the invention has a very low ability to absorb water (test 2 at 60 seconds), about 6 times less than a standard paper, so the water tends to slide off very easily. Even carrying out the same test 2 with other duration times (120 and 300 seconds), it can be seen that sample 1 has a much lower capacity to absorb water than a standard paper (about 7 and 8 times less, respectively).

With reference to test 3, sample 1 of the invention gives the paper 10% more resistance to damp, in case it is exposed to the bad weather. In the standard bag, on the other hand, there are no variations in yield.

With reference to test 4, both in standard environmental conditions of 23° C. and 50% of relative humidity and in extreme tropical conditions of 38° C. and 90% of relative humidity, the sample 1 of the invention grants a better vapor permeability of 82% and 80%, respectively, compared to the standard.

Therefore, the bag of the present utility model, despite being devoid of intermediate plastic layers, thanks to the external coating provided by a layer of paint, provides excellent moisture absorption results, which allows a long shelf life of the product contained in the inside the bag.

Naturally, many modifications and changes of the preferred embodiments described above will be evident to those skilled in the art, still remaining within the scope of the present utility model.

For example, it is possible to implement other embodiments that differ from that of Example 1 seen above, due to the fact a) of having three or more sheets of paper (up to five sheets of paper), instead of two, all coated with a layer of paint on the external side, or b) due to the fact that a polyethylene sheet is interposed between the two sheets of paper, or c) due to the fact to have, in addition to the two or more paper sheets coated with paint, an additional sheet of paper to which the paint layer is not applied on the external side, with or without the interposition of a polyethylene sheet.

Furthermore, the embodiments of the present utility model shown above refer in particular to bags, but, similarly, other embodiments (not described in detail herein) can refer to bundle-type packaging, such as packaging for reams of paper or packaging for food or other food products or useful in the kitchen, without departing from the scope of protection of this utility model, consisting of at least two sheets of paper overlapped on each other, wherein the outer sides of said sheets are coated with at least one layer of hydrophobic paint

Example 4 (Invention)

A bundle type packaging for wrapping a ream of paper or biscuits consists of a single sheet of paper having a weight of about 90 gr/m². The paper sheet is coated by spreading with a layer of hydrophobic paint of the polymer wax type, with a coverage of about 5 gr/m². The hydrophobic paint used is a mixture that contains 1,2-benzisothiazol-3(2H)-one, 5-chloro-2-methyl-2H-isothiazol-3-one (CMIT) and 2-methyl-2H-isothiazol-3-one, with a pH of about 8.5, a relative density of about 1 g/cm³ at 20° C. and a viscosity <1,500 mPas.

Example 5 (Comparison)

As a comparison example 5, a bundle-type packaging is taken and differs from that of the invention shown in Example 4 due to the fact that the single sheet of paper that composes it has not been coated with a layer of hydrophobic paint.

Example 4 of the present invention and Example 5 for comparison were subjected to the same Tests 1-4 described above to which the samples 1 and 2 seen above were subjected.

Similarly to what has been seen in the case of sample 1 (a bag consisting of two overlapped sheets of paper), also in the case of sample 4 of the present invention (wherein the bundle-type packaging consists of a single sheet of paper), the fact that the external surface of the paper sheet has been coated with a hydrophobic paint has allowed to improve the moisture absorption qualities, compared to the comparison sample 5 on which, on the contrary, no coating with hydrophobic paint has been applied.

Therefore, the present utility model is not limited to the preferred embodiments described, shown only by way of example and not limited to, but is defined by the claims below. 

1. Bag or bundle-type packaging comprising at least two sheets of paper overlapped on each other, wherein the external sides of said sheets are coated with at least one layer of hydrophobic paint, characterized in that said paint is distributed on each of said sheets of paper with a weight in the range of about 4 gr/m² to about 9 gr/m².
 2. Bag or bundle-type packaging according to claim 1, comprising at least three sheets of paper overlapped on each other.
 3. Bag or bundle-type packaging according to claim 1, wherein said hydrophobic paint is a water-based.
 4. Bag or bundle-type packaging according to claim 1, comprising a main lateral external surface and at least one lower bottom secured to said main external surface, wherein each of said main lateral external surface and said lower bottom comprises at least two of said sheets of paper overlapped on each other coated with at least one layer of hydrophobic paint.
 5. Bag or bundle-type packaging according to claim 1, further comprising an upper bottom secured to said main external surface, wherein said upper bottom also comprises at least two of said sheets of paper overlapped on each other with at least one layer of hydrophobic paint.
 6. Bag or bundle-type packaging according to claim 1, wherein the internal sides of said at least two sheets are glued to each other at the upper end and the lower end of said sheets so as to create a sort of tube inside the bag.
 7. Bag or bundle-type packaging according to claim 6 wherein the internal sides of said at least two sheets are glued to each other in points arranged at said upper and lower ends.
 8. Bag or packaging according to claim 6, wherein the internal sides of said at least two sheets are glued to each other by means of starch glue or vinyl glue.
 9. Bag or bundle-type packaging according to claim 1, wherein said bag further comprises closure systems along a longitudinal line of the external lateral surface of the bag that extends substantially from said lower bottom to said upper bottom, wherein said systems of closure include escape routes to ensure the escape of air from the inside of the bag.
 10. Bag or bundle-type packaging comprising a single sheet of paper, optionally coupled with at least one other sheet of paper or plastic material, wherein the outer side of said bag or bundle-type packaging is coated with at least one layer of hydrophobic paint having a weight in the range from about 4 gr/m² to about 9 gr/m². 